OpenCATS is an open-source applicant tracking system and recruitment CRM for staffing agencies and hiring teams. Prior to version 0.10.0, activity DataGrid date filtering in "home:CallsDataGrid" and "activity:ActivityDataGrid" uses request-controlled "period", "startDate" and "endDate" parameters without sufficient validation or escaping. The vulnerable code is in "modules/home/dataGrids.php" and "modules/activity/dataGrids.php". The "startDate" and "endDate" values are inserted into SQL string comparisons without safe escaping, and "period" can directly influence generated SQL. An authenticated user with access to the affected DataGrid endpoints can alter the intended query to access sensitive database contents, including user account data, candidate records, contact details, company information, job orders and activity history. A valid OpenCATS login is required; unauthenticated exploitation is not established. This issue is fixed in version 0.10.0.